#include <51func.h>
int main(int argc, char *argv[])
{
    if(fork()){
        wait(NULL);
    }
    else{
        printf("child before, sid = %d\n", getsid(0));
        setsid();
        printf("child after, sid = %d\n", getsid(0));
    }
    return 0;
}

